I had the same problem after switching from the xserver-xorg-video-ati driver to fglrx and then back to xserver-xorg-video-ati after experiencing a memory leak:
https://bugs.launchpad.net/ubuntu/+source/fglrx-installer/+bug/1354350 The problem was the fglrx package installs this file: /etc/modprobe.d/fglrx-core.conf Which includes this line: blacklist radeon Which blacklists the open source radeon driver. I removed /etc/modprobe.d/fglrx-core.conf, rebooted, and my problem was fixed. xrandr was able to see all available resolutions as well as it was able to see multiple monitors. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1364078 Title: Cannot set screen resolution above 1400x1050 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/1364078/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
